I personally can't speak for the rubi shocks, but I know from a racing backgroud that compression dampening and rebound settings for a trail specific vehicle are FAR different than shocks designed for road manners. The biggest factor in the equation that your struggling with is the sway bar. Unfortunately I don't know of anyone making a thicker sway bar... if anything, as far as trail driving, they are a nuiscance. I took mine off. The tires are more of a traction thing - especially wet weather (when comparing what you got rid of vs what you have now), other than that, unless you reduced the size to have a shortr sidewall, the tires will have little impact on the "sloppyness" compared to the suspension elements that are the real cause of the poor handling.
Aside from performance parameters - I know my Sahara shocks that are supposed to be HD shocks are GARBAGE. The bushings are junk, the design is faulted and many guys have blown them out with moderate trail use. So to ask if anything would be an improvent over stock, I would have to say yes.
As for the limits of the road handling abilities - I assume this is your first Wrangler. These Jeeps are Ferrari's compared to the older Jeeps. Sloppy road feel is just something that comes with the turf. It ain't a Cadillac, or a Camry, or even a '85 Corolla. Its a Jeep and we should all be thankful that the JK is what it is. Aksing your JK to drive better on the road is no different that someone on a Porsche forum wanting to know what they can do to make their 911 more trail friendly.